public class Java029 {
    public static void main(String[] args) {
        int[][] arr={{1,2,3},{4,5,6},{7,8,9}};
        diagonal(arr);
    }
    public static void diagonal(int[][] arr){
        int all=0;
        for(int i=0;i< arr.length;i++){
            all+=arr[i][i];
        }
        System.out.println(all);
    }
}
